Cervical spondylosis with muscle atrophy in the shoulder girdle is called cervical spondylotic amyotrophy. Pathophysiology in this condition is not well resolved. Muscle action potential after stimulation of the cortex by magnetic stimulation (MEP) in biceps brachii and T-response muscle action potential after tapping of biceps tendon were recorded in 10 patients who presented with deltoid and biceps paresis. Latency difference between the affected and unaffected side were also measured. Latency differences were more evident in T-response compared to MEP. The results showed that pathological lesions in cervical spondylotic amyotrophy are not localized to the anterior root but also found in the spinal cord or posterior root.
